JPH0328278B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a punch for compression molding powder and granule, which molds the powder and granule filled in a mortar hole by compressing it from above and below, for example. be.

(Prior art) Generally, when manufacturing molded products such as pharmaceutical tablets by compression molding raw material powder,
For example, in the case of a rotary powder compression molding machine, an upper punch and a lower punch are arranged so as to face a rotary disk with a large number of dies arranged around the periphery, and are arranged to be able to slide up and down. The powder is then filled into the mortar hole in which the mortar bottom has been formed, and compression molded using the upper and lower punches.

However, depending on the properties of the powder or granules, the powder or granules may adhere to the tip of the punch, and if this type of adhesion continues to be molded continuously, the adhesion will grow and the attached powder or granules may be removed. This causes the compressed molded product to become stuck, causing part of the compressed molded product to peel off, resulting in loss of marketability such as lack of weight and poor appearance.

This adhesion is particularly severe when foaming agents such as citric acid, tartaric acid, baking soda, sugar, etc. are used as raw materials.

Conventionally, there is a cleaning device that cleans the punch tip surface after compression molding with a rotating brush, etc., so that the next compression molding can be performed with a clean punch tip surface. No. (1986-)
As disclosed in Japanese Patent No. 90283), it is known to provide a synthetic resin body over a lower punch inserted into a mortar to prevent powder from adhering to the lower punch.

(Problems to be Solved by the Invention) Even with such conventional techniques, it is possible to compression mold powder or granules, but the technique that attempts to keep the punch tip surface clean using the cleaning device described above does not. However, the structure is complicated, and there are problems such as the inability to reliably remove deposits, and in addition, those with a synthetic resin body on the lower punch have weak mechanical strength due to the nature of the synthetic resin, and the compression pressure cannot be easily removed. It could only be used for specific molding and had low durability.

In other words, it is ideal for a compression molding punch to be made of a synthetic resin such as tetrafluoroethylene resin, which has extremely less adhesion of powder or granules compared to metal, at least the tip of the punch which comes into contact with the powder or granules. However, there was a problem in that it was necessary to develop a compression molding punch that had a punch tip surface to which the raw material powder and the like would not adhere, something that could not be done conventionally due to the properties of synthetic resins.

(Means for Solving the Problems) In order to solve these problems, according to the present invention, a punch for compression molding powder and granules that is formed by compressing powder and granules filled in a mortar hole is provided. The manufacturing method is characterized in that the synthetic resin of tetrafluoroethylene forming at least the tip of the molding punch is compressed in advance by a mold and a press pressing part with a force higher than the pressure for compression molding the powder. A method for manufacturing a punch for compression molding powder or granular material is provided.

In the above configuration, when the synthetic resin is compressed, a desired shape such as a character or a figure can be formed in a part thereof by the tip of the press pressing part.

In this case, a molding punch for applying a mark or the like to a molded product such as a tablet during compression molding can be manufactured by compressing the molded product without any special process.

(effect) The above technical means works as follows.

It is known that the mechanical strength of synthetic resins, which are generally called plastics, is greatly affected by the molding method such as injection or extrusion during the manufacturing process, the mold, or molding conditions such as temperature and time. There is.

By compressing such a synthetic resin of tetrafluoroethylene in advance at a pressure higher than the compression molding pressure, that is, higher than the pressure applied during compression molding with a molding punch, it is uniformly densified and formed at least on the punch tip surface. The compressed synthetic resin is completely unaffected by the compression molding pressure used and acts as if it can withstand this pressure.

(Example) An example of the present invention will be described with reference to the drawings.
FIGS. 1 and 2 show an embodiment of the present invention.

In FIG. 1, a part 8 is attached to the upper part of the metal part 3.
A punch 1 having a synthetic resin 2 of tetrafluoroethylene embedded therein is housed in a mold 4, and is squeezed by a press pressing section 5 with a pressure higher than the compression pressure that the punch 1 receives as a compression molding punch. .

In this case, as the synthetic resin 2 increases in hardness and shrinks slightly due to compression, the synthetic resin 2 may be formed in advance to be larger by the amount of shrinkage to match the dimensions of the punch 1 required as a compression molding punch. desirable.

FIG. 2 shows the case where the previously compressed punch 1 is used as a compression molding punch, and 6
numeral 7 represents a mortar for filling the raw material powder, and numeral 7 represents a fixing pin that prevents the synthetic resin 2 from coming off.

FIGS. 3 and 4 show another embodiment of the present invention, in which a synthetic resin 2a of tetrafluoroethylene, which will become a compression molding punch, is housed in a mold 4a, and the synthetic resin 2a is inserted into the tip. A punch 1a made of only a synthetic resin 2a having an engraved part 9 on a part of the punch tip surface is formed as shown in FIG. .

FIGS. 5 and 6 show still another embodiment of the present invention, in which a synthetic resin 2b of tetrafluoroethylene, which becomes a compression molding punch, is housed in a mold 4b, and the synthetic resin 2b is A punch 1b having a protrusion 10 on a part of the punch tip surface is formed by pressing with a press pressing part 5b having a desired shape such as letters engraved on the part thereof, as shown in FIG.

In this case, it is desirable that the upper part of the synthetic resin 2b before compression be formed into a spherical shape so that its center protrudes.

(Effects of the Invention) As explained above, the present invention provides a punch for compression molding powder or granular material that has at least the punch tip made of a synthetic resin that is completely unaffected by compression molding pressure and can withstand it sufficiently. A compression molding punch with a punch tip surface to which the raw material powder and granules do not adhere can be provided by using a synthetic resin of tetrafluoroethylene, which can be manufactured in a number of steps, and has extremely less adhesion of powder and granules compared to this metal. It is.

In addition, since it does not adhere to the punch tip surface, it is possible to prevent defects such as insufficient weight, and there is no need for a cleaning device for the punch tip surface, making it possible to easily manage compression molding.

[Brief explanation of the drawing]

The drawings show a method for manufacturing a punch for compression molding powder and granular materials according to the present invention, and FIG. 1 is a vertical cross-sectional view of the main part showing one embodiment, and FIG. 2 is an enlarged vertical cross-sectional view of the main part in the same state of use. , FIG. 3 is a vertical cross-sectional view of the main part showing another embodiment, FIG. 4 is a perspective view of the main part, FIG. 5 is a longitudinal cross-sectional view of the main part showing still another embodiment, and FIG. FIG. In the drawing, 1, 1a, 1b are pestles, 2, 2
a, 2b are synthetic resins of tetrafluoroethylene, 3 are metal parts, 4, 4a, 4b are molds, 5, 5a, 5b
Reference numeral 1 indicates a press pressing part, 6 a die, 7 a fixing pin, 8 a part where the synthetic resin 2 of tetrafluoroethylene is fitted into the metal part 3, 9 a carved part, and 10 a protruding part.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a punch for compression molding powder and granular material by compressing powder and granular material filled in a mortar hole, in which ethylene tetrafluoride forms at least the tip of the molding punch. A method for manufacturing a punch for compression molding powder or granular material, characterized in that the synthetic resin is compressed in advance using a mold and a press pressing part with a force higher than the pressure for compression molding the powder. 2. Powder according to claim 1, characterized in that when the synthetic resin is squeezed, a desired shape such as letters or figures is formed in a part thereof by the tip of the press pressing part. A method for manufacturing a punch for body compression molding.